The present invention relates to device controllers and operating methods therefor and more particularly conveying systems employing such controllers locally.
Existing control systems and control methodologies, particularly those for conveying systems, employ some form of centralized control over multiple device controllers. For example, two device controllers are hard wired interconnected to a programmable logic controller (PLC) or a plurality of PLCs, each being hardwired to device controllers, are hard wired connected to another central PLC. To effect a change in the operation of one device in response to changing conditions for another device, the PLC identifies the changing conditions and sends a signal to the other controller.
Such systems are difficult to modify in the field by the user (i.e, not user friendly). System modifications typically involves re-configuring or replacing each control component (i..e, controller and PLC) in the system. As such, these types of systems are expensive and time consuming and have little flexibility for field modification.
Conveying systems traditionally have been custom designed with centralized controls and complex customized software for tracking articles or goods in movement in the system. Modifications to such systems entail adjustments to the centralized controls, revision to the customized software and the de-bugging required following such changes to assure proper system operation. Further, because the software and controls for each system is customized for each system, it is difficult to combine the control logic with the mechanicals of the conveying system.
There is, therefore, a need for controllers that communicate with each other on a local area basis to control the operation of systems or devices connected to the controllers and need for controllers that de-centralize these control function. Additionally, there is a need for a controllers which do not require hard wired interconnections but use communication protocols and equipment as a means for communicating between controllers. There also is a need for a conveying system that has increased flexibility and controls the flow of goods or articles through the system without centralized control and customized software. Moreover, there-is a need for a conveying system that is modularized in design and operation so customized engineering is not required.
It is, therefore, an object of the present invention to provide a controller that, through communication with other controllers, controls the system or devices using the controllers.
It is another object of the present invention to provide a controller that de-centralizes the control process.
It is a further object of the present invention to provide a conveying system using such a controller that controls individual sections of the conveying system.
It is yet a another object of the present invention to provide a conveying system controller that adjusts the operation of one conveying section in response to communications from other controllers representative of local system performance or problems.
It is yet a further object of the present invention to provide a conveying system controller, a universal controller, that is re-configurable by the user to drive any of the conveying sections making up the conveying system.
It is still yet another object of the present invention for the controller to be re-programmed by the user locally or from a central location using the controller communications network.
The instant invention features a device controller that is used in a system of such controllers as well as a method for controlling the operation of a device using such a device controller. The device controller includes at least one, preferably at least two, bi-directional inflow and outflow communications ports, a processor and an applications program for execution with the processor. The processor processes information and provides outputs, where at least one output controls the device. The applications program includes instructions and criteria for processing the information and providing the processor outputs. Specifically, the applications program includes instructions and criteria for communicating information between and among controllers; instructions and criteria for processing information received by a controller; and instructions and criteria for modifying the operation of a device responsive to the communicated information.
The device controller further includes a read/write memory for storing data and parameters that control the operation of the applications program. The applications program also further includes instructions and criteria for controlling data storage in the read/write memory as well as instructions and criteria for real time tracking of data related to system performance.
To communicate information between and among the controllers of the system, a communications link is established between each pair of controllers. This link is established by electrically interconnecting one bi-directional outflow port of one controller to one bi-directional inflow port of another controller.
The controller of the instant invention may be programmed or re-programmed by means of the RS232 I/O port or by means of the communications network established by the electrically interconnected controllers. To effect programming/re-programming of a controller via the communications links, the applications program further includes instructions and criteria for reprogramming the processor/controller responsive to instructions and information communicated through a bi-directional inflow port.
Also featured is a conveying system having a multiplicity of conveying sections, where each section is provided with a local controller. The local controller for each conveying section, the corresponding conveying section includes at least one, preferably at least two, bi-directional inflow and outflow communications ports, a processor and an applications program for execution with the processor.
The processor processes information and provides outputs, where at least one output controls the corresponding conveying section. The applications program includes instructions and criteria for processing the information and providing the processor outputs. Specifically, the applications program includes: instructions and criteria for communicating information among and between each controllers of the multiplicity of conveying sections; instructions and criteria for processing information received by the controller for the corresponding conveying section; instructions and criteria to control the normal operation of the corresponding conveying section, and instructions and criteria for modifying the operation of the corresponding conveying section responsive to information communicated from the controller of another conveying section.
Each conveying section controller further includes a read/write memory for storing data and parameters that control the operation of the applications program. The applications program also further includes instructions and criteria for controlling data storage in the read/write memory.
A conveying system according to the instant invention utilizes a multiplicity of different section types to transport articles in a controlled manner. For example, the conveying system of the instant invention may include straight sections, accumulation sections, spacer sections, index sections, diverter sections and merge sections. As such, the applications program in each conveying section controller, preferably includes the instruction and criteria to control the operation of any of these different section types.
The applications program accesses the control routines of the specific to the operation of a given type of conveying section (e.g., an index section) by evaluating the data and configuration parameters stored in the read/write memory. For example, the section type is a parameter that is stored in a data table set up in the read/write memory.
In operation, data relating to the articles on the corresponding conveying section is stored in the read/write memory. The applications program also further includes instructions and criteria for real time tracking of articles on each conveying section. Thus, a remotely located host computer, using the communications network established between and among the controllers, can make an inquiry to any controller for such real time information. Further, when articles are transferred from an upstream conveying section to a downstream section, the data stored in the read/write memory of the upstream controller is communicated to the downstream controller.
In specific embodiments, the conveying system further includes a multiplicity of tracking devices to sense the presence of an article. These tracking devices are disposed at the end or beginning of a given section and the section""s controller is appropriately configured for the position of its tracking device. The tracking devices are disposed at various locations through out the conveying system required for proper operation of a conveying section(s) and the system. For example, a tracking device would be located between the end of a spacer section and the next section in the conveying system.
For the first section of the conveying system, a mechanism or device is provided at or proximate the beginning of the first section to provide a positive indication of each article entering into the conveying system. This mechanism or device may be a tracking device, a photo eye or other device known to those in the art for use in detecting the presence of an article. The controller of the first section in response to signals from the mechanism/device assigns a identifier to the article and causes the identifier to be stored in the read/write memory.
A tracking device also is located between the first and second sections, and it is used to determine the length of the articles passing through the first section as well as the presence of the article at the end of the first section. The first and second sections controller operates in conjunction with their tracking device, so the determined length for each article is stored, along with the associated identifier in the read/write memory. Alternatively, the length is determined by the tracking device disposed at the beginning of the first section and the first section controller causes both the identifier and determined length to be stored in the read/write memory.
Similar to the above described device controller, a communications link is established between each pair of controllers of the conveying system by electrically interconnecting one bi-directional outflow port of one conveying section controller to one bi-directional inflow port of another conveying section controller. Further, the conveying system controllers may be programmed or re-programmed by means of the RS232 I/O port or by means of the communications network established by the electrically interconnected controllers and the instructions and criteria included in the applications program.